Transformer



E. THOMSON.

TRANSFORMER.

(No Model.)

No, 454,090. Patnted June 16,1891.

UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF SXVAMPSOOTT, MASSACHUSETTS.

TRANSFORMER.

SPECIFICATION forming part of Letters Patent Nod-54,090, dated June 16,1891. Application filed October 11, 1890. Serial No. 367,851. (Nomodel.)

To all whom it may concern:

Be it known that I, ELIHU THOMSON, a citi zen of the United States,residing at Swamp scott, in the county of Essex and State ofMassachusetts, have invented a certain new and useful Improvement inTransformers, of which the following is a specification.

The invention herein described relates to the construction oftransformers or self-inductive coils, such as are used in systems ofalternating-current distribution. The general method of building thetransformer consists in winding the primary and secondary coils around asectional core, and then surrounding the coils and core with a separatesheath of magnetic material, which completes the magnetic circuit.

My present improvements consist in certain details of construction in atransformer of the character outlined, all as hereinafter pointed out inthe claims.

In the accompanying drawings, Figure 1 shows in perspective atransformer partly built up. Fig. 2 is a side view of the transformerwhen completed. Figs. 3 and 4 respectively illustrate one of thecore-blanks and closed iron frames from which the outside magneticsheath is built up. Fig. 5 shows the core completed; and Fig. 6 isasectional View taken on linens m, Fig. 2.

The central core of the transformer consists of a number of blanks orlaminae of thin sheet-iron or other magnetic material, preferablyrectangular in shape, which are piled up one upon another, and at eitherend of the block thus formed is an end plate D D. The blanks and endplates are securely bound together by an insulated transverse boltorbolts B, which may be Varied in number and location, though thepreferred arrangement is that shown,wherein a single bolt passes upthrough registering holes H in the centers of the blanks and is screwedinto one of the end plates D.

Upon the core, and substantially covering its ends and two of its sides,are the primary and secondary coils C O, which are arranged side by sideor one upon the other, as desired. Surrounding the core and coils is asectional magnetic sheath, which completes the mag netic circuit, aswill be readily understood, and which is built from individual closedframes of iron or other magnetic material. These frames may be slippedover the coils one by one, as indicated in Fig. 1, or, if desired, thesheath may be built up separately and the core and coils passed throughthe central opening left therein. Bottom and top plates F F, ofconsiderable weight and strength, serve as clamping-plates, and thebottom plate is recessed, as at O 0, so as to receive the ends ofcore-plate D, which project, as shown at s, a short distance beyond thesides of the core, and lock the exterior sheath when complete to thecore in such a way as to form a rigid compact structure. The outsideedges of the frame P and clamping-plates are notched or recessed at thecorners and at intervals along the sides, as at U U, and binding-boltsB, which hold the parts of the exterior sheath together, are seated inthese recesses, thus adding to the compactness of the transformerbybringing the bolts within the space bounded by the sides of thesheath. The bolts B may be insulated, so as to prevent theirestablishing an electrical connection transversely of the sheath,although this is not absolutely essential in practice, because theposition given them precludes their becoming the cause or seats ofinduced electric currents. The bolts are held in place by nuts N on theoutside of one of the clamping plates or by any other suitable means,many of which will readily suggest themselves to the constructor.

It is preferred to alternate the iron plates constituting the core andexterior sheath with zinc blanks, after the manner described in a patentgranted to me January 28, 1890, and numbered 420,396; but this is notnecessary, as the iron can be used simply in the ordinary scaledorblackened condition in which it is after being subjected to heatduring annealing.

Vhat I claim as new, and desire to secure by Letters Patent, is-- 1. Thecombination, with arectangular sectional core having two of its sidescovered by the primary and secondary coils wound thereon, and its othersides flush with the ends of the coils, of the closed iron frames ofmagnetic material surrounding the core and coils and completing themagnetic circuit, as described.

2. The combination, in a transformer, of

the primary and secondary coils, sectional core-blanks, and endplates 1) D, one of which projects beyond the sides of the core, withthe closed iron frames and end plates surrounding the core and coils andcompleting the magnetic circuit, the projecting end plate interlockingwith the external sheath, as described.

In testimony whereof I have signed this specification this 9th day ofOctober, 1890. ELITIU THOMSON.

Witnesses:

JOHN W. GIBBONEY, DUGALD MCKILLOP.

